A wobble plate machine functions according to the following principle: When a drive shaft rotates, a wobble plate shaft is caused to move so as to describe a cone about the center axis of the drive shaft. Because the wobble plate shaft is inclined with respect to the center axis of the drive shaft, a wobble plate positioned perpendicular to the wobble plate shaft executes a wobbling motion about a wobble point disposed on the center axis of the drive shaft. A separation web which penetrates the wobble plate and which extends in the axial direction of the drive shaft divides the transport chamber into a suction-side part and a pressure-side part. The wobble plate moves along the side walls of the transport chamber and creates two circumferential transport chambers of variable capacity within the transport chamber. Ideally, the wobble plate contacts the side walls of the transport chamber in sections.
DE-AS 1 090 966 discloses a wobble plate pump, in which the wobble plate is disposed in a transport chamber. Those housing walls of the transport chamber which are disposed opposite the wobble plate are cone-shaped. The plane of the transport chamber is perpendicular to the plane of the drive shaft. The wobble plate is disposed in the transport chamber at an angle, and thus transport chambers, with a variable capacity, are formed on both sides of the wobble plate. When the wobble plate moves in the transport chamber it has the shape of a circular ring whose inside diameter is disposed on a spherical surface of a wobble plate hub. This spherical surface is mounted in appropriately shaped counter-surfaces of the pump housing which encloses the transport chamber.
The wobble plate shaft is mounted in a rotor that is connected to the drive shaft. For this purpose, the rotor has an eccentric bore, positioned at an angle to the center axis of the drive shaft. Two ball bearings are disposed in this bore. Their outer ball races contact the wall of the bore and guide one end of the wobble plate shaft. When the rotor turns, the end of the wobble plate shaft describes a circle about the center axis of the drive shaft, and the wobble plate executes a wobbling motion about the wobble point.
Another driving apparatus is described in the DE-PS 12 77 673. To achieve wobbling motion, the drive axle has an angled section which describes a uniform double cone when the drive shaft rotates. The center of the double cone is the wobble point. Through a needle bearing, a hub is supported on the angled section, to which the wobble plate is connected.
In both of these designs, one difficulty is that the wobble plate shaft must be guided so that the wobble plate contacts the side walls of the transport chamber as well as possible during the entire rotation. However, if there are even the slightest deviations from the calculated ideal dimensions, for example due to inaccuracies of the wall surfaces, distortion of parts through heat expansion or through rolling over foreign bodies, then the wobble plate will not be positioned in the desired angled position. As a result, the wobble plate either is pressed too strongly against the side walls or else high forces arise from the distortions. Such forces could destroy the wobble plate machine and the driving motor. Another risk is the creation of a gap between the wobble plate and the side walls, which would reduce efficiency of the wobble plate machine.
It is therefore an object of the invention to bring the wobble plate into contact with the side walls of the transport chamber in such a way that, when the wobble plate machine is operated, proper contact is obtained and maintained, so that the gap losses will be small and distortions are avoided.